qsqlquerymodel.cpp

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#include "qsqlquerymodel.h"

#include <qdebug.h>
#include <qsqldriver.h>
#include <qsqlfield.h>

#include "qsqlquerymodel_p.h"

QT_BEGIN_NAMESPACE

#define QSQL_PREFETCH 255

void QSqlQueryModelPrivate::prefetch(int limit)
{
    Q_Q(QSqlQueryModel);

    if (atEnd || limit <= bottom.row() || bottom.column() == -1)
        return;

    QModelIndex newBottom;
    const int oldBottomRow = qMax(bottom.row(), 0);

    // try to seek directly
    if (query.seek(limit)) {
        newBottom = q->createIndex(limit, bottom.column());
    } else {
        // have to seek back to our old position for MS Access
        int i = oldBottomRow;
        if (query.seek(i)) {
            while (query.next())
                ++i;
            newBottom = q->createIndex(i, bottom.column());
        } else {
            // empty or invalid query
            newBottom = q->createIndex(-1, bottom.column());
        }
        atEnd = true; // this is the end.
    }
    if (newBottom.row() >= 0 && newBottom.row() > bottom.row()) {
        q->beginInsertRows(QModelIndex(), bottom.row() + 1, newBottom.row());
        bottom = newBottom;
        q->endInsertRows();
    } else {
        bottom = newBottom;
    }
}

QSqlQueryModelPrivate::~QSqlQueryModelPrivate()
{
}

void QSqlQueryModelPrivate::initColOffsets(int size)
{
    colOffsets.resize(size);
    memset(colOffsets.data(), 0, colOffsets.size() * sizeof(int));
}

QSqlQueryModel::QSqlQueryModel(QObject *parent)
    : QAbstractTableModel(*new QSqlQueryModelPrivate, parent)
{
}

QSqlQueryModel::QSqlQueryModel(QSqlQueryModelPrivate &dd, QObject *parent)
    : QAbstractTableModel(dd, parent)
{
}

QSqlQueryModel::~QSqlQueryModel()
{
}

void QSqlQueryModel::fetchMore(const QModelIndex &parent)
{
    Q_D(QSqlQueryModel);
    if (parent.isValid())
        return;
    d->prefetch(qMax(d->bottom.row(), 0) + QSQL_PREFETCH);
}

bool QSqlQueryModel::canFetchMore(const QModelIndex &parent) const
{
    Q_D(const QSqlQueryModel);
    return (!parent.isValid() && !d->atEnd);
}

int QSqlQueryModel::rowCount(const QModelIndex &index) const
{
    Q_D(const QSqlQueryModel);
    return index.isValid() ? 0 : d->bottom.row() + 1;
}

int QSqlQueryModel::columnCount(const QModelIndex &index) const
{
    Q_D(const QSqlQueryModel);
    return index.isValid() ? 0 : d->rec.count();
}

QVariant QSqlQueryModel::data(const QModelIndex &item, int role) const
{
    Q_D(const QSqlQueryModel);
    if (!item.isValid())
        return QVariant();

    QVariant v;
    if (role & ~(Qt::DisplayRole | Qt::EditRole))
        return v;

    if (!d->rec.isGenerated(item.column()))
        return v;
    QModelIndex dItem = indexInQuery(item);
    if (dItem.row() > d->bottom.row())
        const_cast<QSqlQueryModelPrivate *>(d)->prefetch(dItem.row());

    if (!d->query.seek(dItem.row())) {
        d->error = d->query.lastError();
        return v;
    }

    return d->query.value(dItem.column());
}

QVariant QSqlQueryModel::headerData(int section, Qt::Orientation orientation, int role) const
{
    Q_D(const QSqlQueryModel);
    if (orientation == Qt::Horizontal) {
        QVariant val = d->headers.value(section).value(role);
        if (role == Qt::DisplayRole && !val.isValid())
            val = d->headers.value(section).value(Qt::EditRole);
        if (val.isValid())
            return val;

        // See if it's an inserted column (iiq.column() != -1)
        QModelIndex dItem = indexInQuery(createIndex(0, section));

        if (role == Qt::DisplayRole && d->rec.count() > section && dItem.column() != -1)
            return d->rec.fieldName(section);
    }
    return QAbstractItemModel::headerData(section, orientation, role);
}

void QSqlQueryModel::queryChange()
{
    // do nothing
}

void QSqlQueryModel::setQuery(const QSqlQuery &query)
{
    Q_D(QSqlQueryModel);
    QSqlRecord newRec = query.record();
    bool columnsChanged = (newRec != d->rec);
    bool hasQuerySize = query.driver()->hasFeature(QSqlDriver::QuerySize);
    bool hasNewData = (newRec != QSqlRecord()) || !query.lastError().isValid();

    if (d->colOffsets.size() != newRec.count() || columnsChanged)
        d->initColOffsets(newRec.count());

    bool mustClearModel = d->bottom.isValid();
    if (mustClearModel) {
        d->atEnd = true;
        beginRemoveRows(QModelIndex(), 0, qMax(d->bottom.row(), 0));
        d->bottom = QModelIndex();
    }

    d->error = QSqlError();
    d->query = query;
    d->rec = newRec;

    if (mustClearModel)
        endRemoveRows();

    d->atEnd = false;

    if (columnsChanged && hasNewData)
        reset();

    if (!query.isActive() || query.isForwardOnly()) {
        d->atEnd = true;
        d->bottom = QModelIndex();
        if (query.isForwardOnly())
            d->error = QSqlError(QLatin1String("Forward-only queries "
                                               "cannot be used in a data model"),
                                 QString(), QSqlError::ConnectionError);
        else
            d->error = query.lastError();
        return;
    }
    QModelIndex newBottom;
    if (hasQuerySize && d->query.size() > 0) {
        newBottom = createIndex(d->query.size() - 1, d->rec.count() - 1);
        beginInsertRows(QModelIndex(), 0, qMax(0, newBottom.row()));
        d->bottom = createIndex(d->query.size() - 1, columnsChanged ? 0 : d->rec.count() - 1);
        d->atEnd = true;
        endInsertRows();
    } else {
        newBottom = createIndex(-1, d->rec.count() - 1);
    }
    d->bottom = newBottom;

    queryChange();

    // fetchMore does the rowsInserted stuff for incremental models
    fetchMore();
}

void QSqlQueryModel::setQuery(const QString &query, const QSqlDatabase &db)
{
    setQuery(QSqlQuery(query, db));
}

void QSqlQueryModel::clear()
{
    Q_D(QSqlQueryModel);
    d->error = QSqlError();
    d->atEnd = true;
    d->query.clear();
    d->rec.clear();
    d->colOffsets.clear();
    d->bottom = QModelIndex();
    d->headers.clear();
}

bool QSqlQueryModel::setHeaderData(int section, Qt::Orientation orientation,
                                   const QVariant &value, int role)
{
    Q_D(QSqlQueryModel);
    if (orientation != Qt::Horizontal || section < 0 || columnCount() <= section)
        return false;

    if (d->headers.size() <= section)
        d->headers.resize(qMax(section + 1, 16));
    d->headers[section][role] = value;
    emit headerDataChanged(orientation, section, section);
    return true;
}

QSqlQuery QSqlQueryModel::query() const
{
    Q_D(const QSqlQueryModel);
    return d->query;
}

QSqlError QSqlQueryModel::lastError() const
{
    Q_D(const QSqlQueryModel);
    return d->error;
}

void QSqlQueryModel::setLastError(const QSqlError &error)
{
    Q_D(QSqlQueryModel);
    d->error = error;
}

QSqlRecord QSqlQueryModel::record(int row) const
{
    Q_D(const QSqlQueryModel);
    if (row < 0)
        return d->rec;

    QSqlRecord rec = d->rec;
    for (int i = 0; i < rec.count(); ++i)
        rec.setValue(i, data(createIndex(row, i), Qt::EditRole));
    return rec;
}

QSqlRecord QSqlQueryModel::record() const
{
    Q_D(const QSqlQueryModel);
    return d->rec;
}

bool QSqlQueryModel::insertColumns(int column, int count, const QModelIndex &parent)
{
    Q_D(QSqlQueryModel);
    if (count <= 0 || parent.isValid() || column < 0 || column > d->rec.count())
        return false;

    beginInsertColumns(parent, column, column + count - 1);
    for (int c = 0; c < count; ++c) {
        QSqlField field;
        field.setReadOnly(true);
        field.setGenerated(false);
        d->rec.insert(column, field);
        if (d->colOffsets.size() < d->rec.count()) {
            int nVal = d->colOffsets.isEmpty() ? 0 : d->colOffsets[d->colOffsets.size() - 1];
            d->colOffsets.append(nVal);
            Q_ASSERT(d->colOffsets.size() >= d->rec.count());
        }
        for (int i = column + 1; i < d->colOffsets.count(); ++i)
            ++d->colOffsets[i];
    }
    endInsertColumns();
    return true;
}

bool QSqlQueryModel::removeColumns(int column, int count, const QModelIndex &parent)
{
    Q_D(QSqlQueryModel);
    if (count <= 0 || parent.isValid() || column < 0 || column >= d->rec.count())
        return false;

    beginRemoveColumns(parent, column, column + count - 1);

    int i;
    for (i = 0; i < count; ++i)
        d->rec.remove(column);
    for (i = column; i < d->colOffsets.count(); ++i)
        d->colOffsets[i] -= count;

    endRemoveColumns();
    return true;
}

QModelIndex QSqlQueryModel::indexInQuery(const QModelIndex &item) const
{
    Q_D(const QSqlQueryModel);
    if (item.column() < 0 || item.column() >= d->rec.count()
        || !d->rec.isGenerated(item.column()))
        return QModelIndex();
    return createIndex(item.row(), item.column() - d->colOffsets[item.column()],
                       item.internalPointer());
}

QT_END_NAMESPACE